A '55?
Put in a 6.0 w/ LSA in my dads '57 with a 4l80, only using a 6 rib pulley, it startdd slipping at 9.5#'s of boost at 3500 and was down to 7 by 5500, did 502whp. Swapped the pulley for a griptec, hopeful for 550-575. All stock 275k mile engine, had the heads looked at, and put in a BTR...